Rice varietal screening: Relationship between certain Agronomic Parameters and Tolerance to Iron Toxicity

One of the limitations to the development of rice cuktivars which are tolerant to iron toxicity has been the lack of efficient screening techniques. Field and screenhouse experiments were carried out in Cote d'Ivoire between September 1994 and June 1996 to study the relationship between iron toxicity and some agronomic parameters, with the objective of improving the method of screening. Twenty eight varieties (treatments) were transplanted, 21 days after sowing, into adjacent iron toxic and non-toxic fields in Korhogo in northern Cote d'Ivoire. A randomized complete block design was used with three replications. Recommended rates of fertilizers were applied. Leaf symptoms of iron toxicity were scored using the IRRI scale (1 - 9). Data was also taken on the number of tillers at the maximum tilering stage, plant height at maturity and yield and its components. Iron toxicity symptoms ranged between 3-7. Significant relationships were observed between iron toxicity tolerances and reduction in plant height (r = 0.61) and reduction in yield (r = 0.63). No such relationship was however observed between iron toxicity tolerance and reduction in tillers. We conclude that reduction in grain yield and plant height are good criteria for assessing materials for tolerance to iron toxicity but reduction in tiller numbers is not. JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 1 Number 1, July (1998) pp. 29-3